Post driver safety latch

ABSTRACT

A safety latch for supporting a post in a post driver while the post is being driven into the ground. A post-engaging roller is mounted on a lever arm that is pivotally attached to the post driver and moveable between a released position for positioning of a post in the post driver and a working position where the roller is in supporting engagement with the post. A spring biases the roller to maintain supporting engagement with the post while it is driven. In a preferred embodiment, the spring is part of an over-center device for biasing the safety latch to both the released and working positions depending on which side of center the lever arm is positioned.

This application claims priority to U.S. patent application Ser. No. 60/623,325, filed Oct. 29, 2004.

BACKGROUND OF THE INVENTION

The invention relates generally to post drivers and, more specifically, to a safety device for a hydraulic post driver.

Hydrauic post drivers are used in the setting and driving of posts into the ground. The drivers are usually carried on a prime mover, such as a truck, agricultural tractor, or the like. The prime mover transports the driver to the desired position and then uses pressurized hydraulic clued from the prime mover to drive the post into the ground. An example of a hydraulic post driver is described in U.S. Pat. No. 2,940,267, which is incorporated herein by this reference.

Even though warned to use a tool or similar device to hold the post, if needed, while using the post driver, users would sometimes ignore the warnings and use their hands to hold or steady the post. The present device holds the post in position and will reduce the likelihood that a user will endanger himself while using the post driver.

SUMMARY OF THE INVENTION

A hydraulic post driver includes a frame inside of which the post is positioned in a vertical orientation during the driving procedure. A hydraulic ram is supported above the frame and presses against the top of the post to drive it into the ground. Because the frame must be open to receive the post, there is a possibility that the post can be displaced from the frame during the driving procedure. The invention consists of a support that holds a post in position relative to a post driver during the post driving procedure. The support is mounted on the frame adjacent the top end section. It includes an arm member that is mounted for swinging movement about a vertical axis of the support between a released position swung away from the frame and a working position swung toward the frame. A post-engaging roller is mounted on the arm member and is brought into and out of supporting engagement with the post as the arm member is swung toward and away from the frame. A spring-loaded, over-center device biases the roller into supporting contact with the post as it is being driven into the ground. After the post has been driven into the ground, the arm member is swung away from the frame to open the frame for insertion of another post to be driven.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a front elevational view of the invention shown holding a post in position for driving by a post driver.

FIG. 2 is an upper perspective of the invention in its open position.

FIG. 3 is an enlarged front view of the invention in its closed or working position holding a post.

FIG. 4 is a top view of the invention in its open position.

FIG. 5 is a top view of the invention in its shown in an intermediate position between it open and closed positions.

FIG. 6 is a top view of the invention in its closed position.

DESCRIPTION OF THE INVENTION

Illustrated in FIG. 1, generally at 10, it the post support of the present invention shown mounted on a frame 12 of a post driver inside of which is shown a post 14. Above the frame 12 is a hydraulic cylinder 16 that contacts the top of the post 14 to drive it into the ground.

The post support 10 is shown in its open or released position in FIGS. 2 and 4. It includes a plate 18 mounted to a side of the frame 12. An arm member 20 is mounted to the plate 18 for swinging pivotal movement about an axis defined by a pin 22. The arm member 20 includes a first section 24 and a second section 26. A post-engaging roller 28 is supported centrally on the arm member 20 approximately at the junction between the two sections. The free end of the second section 26 includes a handle 30 that is grasped by a user when swinging the arm member 20.

A spring 32 interconnects the first section 24 and the plate 18 at a position rearwardly of the pin 22. The spring 32 biases the arm member 20 toward its mounting on the plate 18. A stop 34 is provided that holds the arm member 20 in its released position as shown in FIGS. 2 and 4 against further movement by the spring 32.

In use to engage and support the post 14, the arm member 20 is pivoted toward the frame 12 to bring the roller 28 into supporting contact engagement with the post 14, as illustrated in FIGS. 1, 3, and 6. The spring 32 biases the arm member 20 and associated roller 28 toward the post 14 once the arm member 20 has been pivoted toward the post 14 bringing the attachment point of the spring 32 on the first section 24 past the pivot axis as defined by the pin 22. Accordingly, the spring 32 acts as an over-center device. An intermediate position is illustrated in FIG. 5, wherein the arm member 20 is approaching the center position.

In use, the post driver is moved to the desired position and a post 14 is inserted into the frame 12. The arm member 20 is pivoted from the open position (FIG. 4) through the intermediate position (FIG. 5) to its post engaging position wherein the roller 28 is in contact with the post 14 (FIG. 6). Thereafter, as the post 14 is driven into the ground, the post support 10 serves to hold the post 14 in the desired position within the frame 12, with the roller 28 rolling along the surface of the post 14. After the post 14 has been driven, the arm member 20 is pivoted to its released or open position so that the post driver can be moved to the next working location.

The foregoing description and drawings comprise illustrative embodiments of the present inventions. The foregoing embodiments and the methods described herein may vary based on the ability, experience, and preference of those skilled in the art. Merely listing the steps of the method in a certain order does not constitute any limitation on the order of the steps of the method. The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited. Those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention. 

1. A post driver safety latch, comprising: (a) mounting apparatus secured to the post driver; (b) a lever arm mounted on the mounting apparatus for pivotal movement; (c) engagement means on the arm member for engaging and supporting the post; and (d) biasing means for biasing the arm member toward the post driver to maintain the engagement means in supporting engagement with the post.
 2. A post driver safety latch as defined in claim 1, wherein the engagement means comprises a roller.
 3. A post driver safety latch as defined in claim 1, wherein the biasing means comprises an over-center apparatus.
 4. A safety latch for supporting a post inside a post driver, comprising: (a) mounting apparatus secured to the post driver; (b) a lever arm mounted on the mounting apparatus for pivotal movement between a released position and a working position; (c) post engagement apparatus movable with the lever arm between a released position and a working position in supporting engagement with the post; and (d) a spring biasing the arm member toward the working position to maintain the post engagement apparatus in supporting engagement with the post.
 5. A safety latch as defined in claim 4, further comprising an over-center apparatus wherein the spring biases the lever arm toward the released position when the lever arm is on a first side of the center position and toward the working position when the lever arm is on the other side of the center position. 